It is previously known in the art to use metallocene catalysts to polymerize olefins to form high molecular weight polyolefin products. Examples include Group 4 metal compounds containing one or more cyclopentdienyl ligands or derivatives thereof, as disclosed in U.S. Pat. No. 4,530,914, U.S. Pat. No. 4,871,705, U.S. Pat. No. 4,937,299, U.S. Pat. No. 5,017,714, U.S. Pat. No. 5,055,438, U.S. Pat. No. 5,096,867, U.S. Pat. No. 5,120,867, U.S. Pat. No. 5,124,418, U.S. Pat. No. 5,198,401, U.S. Pat. No. 5,210,352, U.S. Pat. No. 5,229,478, U.S. Pat. No. 5,264,405, U.S. Pat. No. 5,278,264, U.S. Pat. No. 5,278,119, U.S. Pat. No. 5,304,614, U.S. Pat. No. 5,324,800, U.S. Pat. No. 5,347,025, U.S. Pat. No. 5,350,723, U.S. Pat. No. 5,384,299, U.S. Pat. No. 5,391,790, U.S. Pat. No. 5,391,789, U.S. Pat. No. 5,399,636, U.S. Pat. No. 5,408,017, U.S. Pat. No. 5,470,993, U.S. Pat. No. 5,491,207, U.S. Pat. No. 5,455,366, U.S. Pat. No. 5,534,473, U.S. Pat. No. 5,539,124, U.S. Pat. No. 5,554,775, U.S. Pat. No. 5,621,126, U.S. Pat. No. 5,684,098, U.S. Pat. No. 5,693,730, U.S. Pat. Nos. 5,698,634, 5,703,187, 5,710,297, U.S. Pat. No. 5,712,354, U.S. Pat. No. 5,714,427, U.S. Pat. Nos. 5,714,555, 5,728,641, 5,728,839, 5,753, 577, 5,767,209, 5,770,753, 5,770,664, 5,972,020, 6,034,002, 6,040,041, 6,150,297, 6,376,406, and elsewhere.
Despite the advance in the art, particular higher use temperature, obtained by such prior art metal complexes as were disclosed in the foregoing references, there remains a desire for improved metal complexes capable of even further increase in use temperature that are still capable of forming catalyst compositions useful in producing polymers having high molecular weights and, for polymerization of ethylene/higher α-olefin copolymers, high incorporation of comonomer. The subject compositions of this invention show unexpected improvement in these desirable features.